A lithographic apparatus is a machine that applies a desired pattern onto a substrate or part of a substrate. A lithographic apparatus can be used, for example, in the manufacture of flat panel displays, integrated circuits (ICs) and other devices involving fine structures. In a conventional apparatus, a patterning device, which can be referred to as a mask or a reticle, can be used to generate a circuit pattern corresponding to an individual layer of a flat panel display (or other device). This pattern can be transferred onto all or part of the substrate (e.g., a glass plate), by imaging onto a layer of radiation-sensitive material (resist) provided on the substrate.
Instead of a circuit pattern, the patterning device can be used to generate other patterns, for example a color filter pattern or a matrix of dots. Instead of a mask, the patterning device can comprise a patterning array that comprises an array of individually controllable elements. The pattern can be changed more quickly and for less cost in such a system compared to a mask-based system.
In lithography using a patterning device comprised of an array of individually controllable elements, it has been known to use patterning devices in which each of the individually controllable elements may be set either to a first state, in which radiation is transmitted to the substrate, or a second state, in which radiation is not transmitted to the substrate. Such a device may be referred to as a black and white contrast device.
Using such a device, a pattern may easily be set by selecting each individually controllable element to be in either the first state or the second state according to the position within the pattern. It is therefore computationally relatively straightforward to convert a desired pattern into control signals for the patterning device. Furthermore, the arrangement may be used in a similar manner to a mask-based system. For example, in a corresponding manner to a mask-based system, for a desired pattern to be formed on a substrate, the pattern may be prepared using known optical proximity correction (OPC) techniques, and once the pattern is determined, the control signals for the patterning device generated.